The safe operation of an elevator system is generally ensured with a safety gear that grips the guide rail. A safety gear can be used for stopping the elevator car or the counterweight. A safety gear can be activated for different reasons, such as owing to overspeed of the elevator car; a safety gear can also be activated e.g. when the elevator car is moving on service drive into a part of the elevator hoistway that is reserved as a working space of a serviceman. A safety gear can also be used e.g. to prevent the drifting of an elevator car with doors open from the stopping floor of the elevator. The frame of the safety gear is generally fixed in connection with the elevator car. The frame normally comprises a housing, which contains a braking surface towards the elevator guide rail, and inside which housing the elevator guide rail is disposed. Likewise the housing comprises a wedge or roller, which when the safety gear operates meets the elevator guide rail and is disposed on a track in the housing. The elevator guide rail is between the braking surface and the wedge or roller. The track is shaped such that when the wedge or roller moves on the track in the direction of the guide rail, the guide rail presses against the braking surface under the effect of the wedge or roller producing braking, which stops the elevator car. The safety gear generally stops downward movement of the elevator car; however, safety gears that operate upwards or in two directions are also known in the art.
The aforementioned wedge or roller of the safety gear is pushed on the track increasingly tighter against the guide rail as the gripping progresses. For detaching a gripped elevator car, the elevator car must be pulled in the opposite direction with respect to the propagation direction of the gripping. Owing to the operating principle of a safety gear, detaching a gripped elevator car generally requires a great deal of force. For this reason, a Tirak hoist or corresponding separate hoisting device has conventionally been used for detaching an elevator car.